Air cushioned wheeled base



Oct. 29, 1968 A. G. BILLIN ET AL AIR CUSHIONED WHEELED BASE 2Sheets-Sheet 1 INVENTORS. ARTHUR GILBERT BILLIN 5O WALTER LEE REMLEYATTORNEY Oct. 29, 1968 A, G. BILLIN ET AL. 3,407,896

AIR CUSHIONED WHEELED BASE 2 Sheets-Sheet 2 Filed Nov. 21. 1966 FIG?) W.L SH RB m. mm vw mmm R U m R A WALTER LEE REMLEY ATTORN EY UnitedStates Patent 3,407,896 AIR CUSHIONED WHEELED BASE Arthur GilbertBillin,Rochester, and Walter Lee Remley, Penfield, N.Y., assignors toRitter Pfaudler Corporation, Rochester, N.Y., a corporation of New YorkFiled Nov. 21, 1966, Ser. No. 595,769 6 Claims. (Cl; 180-119) ABSTRACTOF THE DISCLOSURE A dental chair having a pair of forward locatedrollers, a rearward located lip and a single rearward located groundeffect device, the rollers and the groundeffect device together forminga stable, three point support when air is supplied to the ground effectdevice for moving the chair along a floor surface, the rearward locatedlip engaging the floor surface and together with the forward locatedrollers forming a stable, three point support when air is not suppliedto the ground effect device for immobilizing the chair.

This invention relates generally to chairs for supporting dentalpatients and more specifically, to an air cushion base for such chairswhich permit smooth relatively friction free movement of the chair alonga floor surface.

A common arrangement in a dentist office has the dental chair positionedadjacent a console. The console is usually stationary and contains suchapparatus as a power supply, air compressor, lamps, drills, cuspidor andother instruments necessary for performing dental work. The chair,however, is usually quite mobile and can be raised, lowered, tilted,swiveled and in some designs may be moved on .wheels guided by. floormounted tracks. This permits the dentist to place the patient in theposition most convenient for performing the work required.

The common practice in constructing dental chairs is to have the chairswivel on the pedestal or stand which supports the seat of the chair.Because this pedestal is located directly beneath the seat of the chairswinging, say the patients upper body portion, through an arc will causehis lower body portion to swing in the opposite direction through anequal arc. Therefore, care must be taken when swiveling the chair toprevent bumping the patient against any nearby piece of apparatus orother object. Accordingly, it is an object of our invention to provide adental chair in which the vertical axis of rotation is located at somepoint forward of the patient, thereby permitting a relatively largearcuate movement of the patients upper body portion without acorresponding large arcuate movement of the patients lower body portion.

If the chair is movable with respect to the floor sur face, provisionmust be made to insure that the chair does not move while the dentist isworking on the patient, as any unwanted or unexpected movement mayresult in injury to the patient. Therefore, it is another object of ourinvention to provide a mobile chair which presents a stable at restplatform for safe performance of work in the oral cavity.

One method for moving the chair along the floor surface is to mount thechair on tracks attached directly to the floor. While this arrangementdoes provide smooth, relatively friction free motion, certain otherdrawbacks are created. For example, the tracks present an obstacle tothe free passage of rolling equipment close to the chair and the lengthof the tracks define a limit beyond which the chair cannot move.Therefore, it is yet another object of our invention to provide a dentalchair which can move freely over a floor surface unguided by trackmembers.

A more recent inovation for moving dental chairs is to provide the chairwith an air cushion device in the chair base which device, wheninflated, will permit the chair to 3,407,896 Patented Oct. 29, 1968float on a thin film of air as shown, for example, in the Deeley andStram Patent No. 3,254,733. Devices which float a load on an air cushionare commonly known as ground effect devices. A typical ground effectdevice is illustrated in a patent to H. A. Mackie No. 3,161,247. An airsupply is readily available in dentists oflices because low pressure airis used to run high-speed drills and other equipment. However, aircushion devices themselves have several drawbacks when applied to suchtop-heavy equipment as dental chairs. For example, one large air cushiondevice for lifting the entire chair may be unstable as a single aircushion device may not be able to adequately compensate for the weightshift as'might be the case when the patient goes from a seated positionto a reclining position. If a relatively large patient is seated in achair, any shift in position may cause the center of gravity to moveoutside of the area covered by the air cushion device causing the chairto tilt and bind on the floor surface when the device is inflated. Insuch a situation, the dentist must either return the patient to anupright position when moving him, or the dentist must provide some ofthe lift himself. Other air cushion devices employing three air podsarranged in a tripod configuration have been used to lift loads.However, here too, the pods may not be able to compensate for weightshift unless separate controls are provided to regulate the flow of airto each pod or the dentist himself balances the load while moving thechair and patient. Therefore, it is a further object of our invention toprovide an air cushion base for dental chairs which can compensate forany weight shift to prevent the base from binding on the floor surface.

In both instances, when either one large air cushion device or threesmaller air pods are used, the entire combined weight of patient andchair is lifted by the flow of air. The escape of this air from betweenthe ground effect device and the floor surface does not lend itself tohygienic conditions as any dust and bacteria in the dentists office willbe blown about. One method of preventing the objectionable escape of airhas been to build an air return into the ground effect device whichincreases the cost of production. Therefore, it is an additional objectof this invention to provide an air cushion base for dental chairs whichgreatly reduces the amount of escaping air without adding to the cost ofproduction.

These and other objects, advantages and characterizing features of ourinvention will become more apparent upon consideration of the followingdetailed description thereof, in conjunction with the accompanyingdrawings depicting the same, in which:

FIGURE 1 is a side elevation of the seat, chair frame, chair support andair cushion base, the solid line indicating the seat and chair frame ina fully reclined position and the dotted line reflecting the seat andchair frame in an upright position.

FIGURE 2 is a view in cross section of the air cushion base showing theair pod in a deflated condition.

FIGURE 3 is a bottom view of the base.

FIGURE 4 is an elevation view in section of the rearward portion of thebase showing the air pod in an inflated condition.

FIGURE 5 is a schematic representation of the plan view of the aircushion base with the dotted lines illustrating the manner in which thebase can be pivoted about on the roller members.

A dental chair constructed in accordance with our invention can becharacterized in one aspect thereof by the provision of a generallyoblong-shaped base carrying a pedestal for supporting the chair above afloor surface, a pair of roller members journaled to the forward end ofthe base and an air cushion pod housed at the rear of the base, the airpod when inflated acting to raise the rear of the base off of the floorto reduce friction so that the chair can be rolled or pivoted about onthe roller members.

Referring now in detail to the drawings, FIGURE 1 shows a dental chairgenerally indicated at and a console 12 which constitutes no part ofthis invention. Console 12 contains the equipment necessary forperforming drilling, filling and extracting operations, a cuspidor andother associated dental apparatus (not shown). Chair 10 includes a seatportion 14, a tiltable backrest 16 and a pedestal 18 for supporting theseat above a floor surface 20. Pedestal 18 houses the controls andhydraulic system (not shown) necessary for hydraulically raising andlowering the dental chair or tilting backrest 16. A button panel 22 isincorporated into backrest 16 for activating the hydraulic equipment.

As shown in FIGURE 1, pedestal 18 is supported at its lower end on theair glide wheeled base of our invention generally designated at 30. Inthe present invention,

pedestal 18 is firmly fixed to base 30 and no provision is made forallowing the dental chair to swivel on the base or pedestal.

Referring now to the invention as shown in FIGURE 2, air glide base 30is shown to include a downward opening housing 32. Housing 32 has aforward portion 34, a raised central portion 36 for supporting pedestal18 and a rearward portion 38. As shown in FIGURES 2 and 3, forwardportion 34 is provided with a plurality of spaced members 40 formedintegrally with housing 32 for sup porting an axle 42. Journaled toeither end of axle 42 are rollers 44 which extend slightly through thedownward opening housing to support the forward portion of housing 32above floor surface 20. Rollers 44 are preferably cylindrical, althoughother rolling members such as a ball and socket may be used in theirplace. Cylindrical rollers 44 are preferred because this configurationprovides dental chair 10 with maximum support and stability. Thecylindrical shape resists any force tending to move the base axiallywith respect to the rollers. Other rolling members such as ball andsocket rollers, or casters may not provide this stability against axialmovement. As will be seen from FIGURES 1 and 2, the axis of rotation ofcylindrical rollers 44 is located far forward of pedestal 18 forpurposes explained hereinbelow.

Formed integral with the rearward portion 38 is a generallysemi-circular downward projecting lip 46 (FIG- URES 2-4). Lip 46 isadapted to rest on and frictionally engage floor surface providing abrake to effectively prevent movement of the dental chair. Thus, withlip 46 resting on the floor, the dental chair is maintained in a stabletripod supported position. Lip 46 forms the rear leg of the tripod andeach of roller members 44 forms a forward leg.

Located within rearward portion 38 of housing 32 is a ground effectdevice generally designated at 50. Ground effect device 50 (FIGURE 4) iscommonly known as an air pod having a cylindrical backing plate 52firmly affixed to the under surface of rearward portion 38 and aflexible inflatable membrane 54 attached by heat sealing about theperiphery of backing plate 52. Membrane 54 is attached at its centerportion 56 to backing plate 52 by any suitable means such as a heatseal, and has a plurality of radially spaced openings 58 formed throughthe membrane for purposes set out hereinbelow. An inlet 60 extendsthrough rearward portion 38 and backing plate 52 to permit theintroduction of low pressure air between the backing plate and membrane54 to inflate the membrane. For convenience, the controls to initiateinflation of the membrane can be included in button panel 22.

As shown in FIGURE 4, air which is introduced from a source (not shown)through inlet 60 and into the air pod inflates fabric-like membrane 54.Since the membrane is attached at its center portion to the backingplate, inflation of the membrane further causes it to assume a toroidalshape. Inflating the membrane further causes it to expand through thedownward opening of housing 32 and bear against floor surface 20,lifting lip 46 off of the floor surface. Air escaping through radiallyspaced openings 58 forces its way between the membrane and the floorsurface to form a thin film of air between membrane 54 and floor surface20. This thin film of air greatly reduces the friction between membrane54 and floor surface 20 which permits the chair to be easily moved abouton cylindrical roller members 44 with a minimum of effort. Since only aportion of the entire combined weight of patient and chair is supportedby air pod 50, the area of the air pod is greatly reduced therebyreducing the amount of escaping air.

With the air pod inflated, dental chair 10 remains tripod supported,each of the cylindrical roller members 44- continuing to form one leg ofthe tripod and the air pod now providing the third leg of the tripod.With this arrangement, dental chair 10 can be rolled forward or backwardwith a minimum of effort.

As stated hereinabove, the axis of rotation of cylindrical rollers 44 iswell forward of the pedestal 18. With this arrangement and with air pod50 inflated, the back section of the chair can be swung from side toside as desired to better. position the chair in relation to console 12for performing the work required. This eliminates the need for havingpedestal 18 swivel on base 30. Eliminating a swivel in base 30 providesa more rigid construc tion which is desirable for the safety of thepatient. As shown in FIGURE 5, the axis about which chair 10 can berotated is not fixed as is the case in chairs having their seat swiveledto a pedestal. Therefore, the dentist can select the point about whichhe wishes to pivot dental chair 10. For example, he can pivot the chairabout one or the other of the cylindrical rollers 44, some point betweenthese two rollers or some point which lies entirely outside of the base.

Thus, it will be appreciated that the present invention accomplishes itsintended objects providing a dental chair which is completely stable yetwhich can be moved along a floor surface quickly and easily with aminimum of effort. Employing a ground effect device to greatly reducefriction allows the chair to be moved with a minimum of effort.Providing a pair of cylindrical roller members to carry a greaterportion of the weight of the chair provides stability withoutsacrificing mobility. With air pod 50 deflated and with lip 46 restingon floor surface 20, a stable and effective brake is provided whichprevents any unwanted or unexpected movement of the dental chair.Eliminating the need for a swivel also adds to the stability of thechair and eliminates the necessity of a locking device to keep the chairfrom swiveling. Furthermore, by moving the point about which the chaircan be pivoted forward of the pedestal, the head and upper body portionof the patient can be moved through a relatively large arcuate distancewhile moving the lower body portion of the patient through a relativelysmall arcuate distance. With the pivot point located directly beneaththe patient in pedestal 18 as taught by the prior art, both the upperand lower body portions of the patient moved through the same arcuatedistance when the chair was pivoted. In the present invention, the chaircan be pivoted away from console 12 to provide room for an assistantwithout having the lower body portion of the patient come in contactwith the console.

We claim:

1. A movable stand for supporting a structure above a planar surfacecomprising:

(a) a unitary base platform having a first portion adapted to rest onsaid planar surface and a second portion;

(b) a pair of axially spaced rotable members journaled to said baseplatform adjacent said second portion for supporting the same above saidplanar surface; and

(c) an air pod device attached to said base platform adjacent said firstportion for lifting said first portion 01f of said planar surface whenair is supplied to said device wherein an air gap is formed between saiddevice and said planar surface, whereby said stand is movable andinterrupting the air supply to said device causes said stand to becomeimmovable.

2. A movable stand as set forth in claim 1 wherein said air pod deviceis located at one end of said base platform and said rotatable membersare located at another end of said base platform, said device androtatable members together providing a stable, threepoint support forsaid base platform when air is supplied to said device for moving saidstand along said planar surface.

3. A movable stand as set forth in claim 1 wherein said base platform isprovided with a downward projecting portion located at one end of saidbase platform adjacent said first portion, said downward projectingportion being adapted to rest on and frictionally engage said planarsurace, said projection and said pair of axially spaced rotatablemembers together providing a stable, three-point support for said baseplatform for immobilizing said stand when air is not supplied to saidair pod device.

4. A movable stand as set forth in claim 1 wherein said pair of axiallyspaced rotatable members are journaled to a fixed axis lyingsubstantially perpendicular to a line passing through the midpoint ofsaid axis and the center of said air pod device.

5. A movable stand as set forth in claim 1 wherein said pair of axiallyspaced rotatable members are cylindrical rollers, the cylindrical shapeof said rollers acting to resist movement of said stand about a verticalaxis when air is not supplied to said air pod device.

6. In combination with a dental chair having a seat, a tiltable backrest and a pedestal for supporting said seat above a floor surface, anair cushioned wheeled base comprising:

(a) a downward opening housing having a central portion for carryingsaid pedestal, a rearward portion adapted to rest on said floor surfaceand a forward portion;

(1:) an air pod device attached within said housing adjacent saidrearward portion, said device adapted to support said rearward portionabove said floor surface wherein an air gap is formed therebetween whenair is supplied to said device;

(c) a pair of rotatable members attached to said forward portion andextending through said downward opening to support said forward portionabove said floor surface;

(d) said pair of rotatable members and the rearward portion of saidhousing resting on said floor surface providing a stable, immovable,three-point support for said dental chair when air is not supplied tosaid ground effect device; and

(e) said pair of rotatable members arid said air pod device providing astable, movable, three-point support for said dental chair when air issupplied to said device.

References Cited UNITED STATES PATENTS 3,239,022 3/1966 Dolphin l25 X3,254,733 6/1966 Deeley et al 180-123 3,261,177 7/1966 Am-ann et a1180-125 X 3,326,311 6/1967 Jung 180-126 A. HARRY LEVY, Primary Examiner.

